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VVTi throttle problem following clutch change?


James

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My Supra has started to experience an occasional fault when at WOT.

 

Running from cold through to hot (90deg oil and water temps) there are no apparent issues if I am driving 'normally'. Even at 3/4 throttle, making significant boost there is no problem.

 

When I reach WOT everything just drops off entirely, as if I had put the car into neutral and took my foot off of the accelerator. As soon as I take my foot off of the throttle and reapply it, the car works as normal again. It then faulters at WOT once again. If I turn the engine off and on again, the problem goes away for a moment, before returning again shortly after.

 

On one occasion, this happened such that the throttle stopped working entirely at any position. I pulled over, put the car into neutral and tested the revs - nothing at all. When I then turned the engine off and back on again, it came back to life as if nothing had happened. It boosted properly at WOT and all was great. Then the same happened at WOT shortly after again.

 

The idle is spot on. The oil temperature, oil pressure, fuel pressure are all as they should be as well. No issues there.

 

I'm thinking it would be the throttle position sensor or cam position sensor? Possibly a MAP sensor issue?

 

Any ideas/experiences welcomed.

 

Thanks!

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This may help? :)

 

http://www.2jzgarage.com/2013/07/etcs-i-dbw-system-troubleshooting/#more-863

 

I also have a spare VVTi throttle, but I would be reluctant to part with it as they are hard to find. But if you get stuck then I will consider it. :)

 

Thanks for that Jason - I did find that site last night as well but will go through it properly again this evening!

 

Just pulled up some fault codes and noted 13, 24 & 34. That seems to be crank position sensor, air intake temp sensor and actuator/VSV problems.

 

All very frustrating as there was nothing occurring before my clutch change. It just never ends!

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You could always borrow my VVTi throttle to help diagnose the fault?

 

Love having a VVTi, but the lack of knowledge regarding them can be a PITA. Hopefully now that the yanks are starting to use them it will help solve a lot of these issues. I'm ditching the stock throttle/plenum setup when I go single though, will use a proper FBW throttle from a 'vette or similar.

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You could always borrow my VVTi throttle to help diagnose the fault?

 

Love having a VVTi, but the lack of knowledge regarding them can be a PITA. Hopefully now that the yanks are starting to use them it will help solve a lot of these issues. I'm ditching the stock throttle/plenum setup when I go single though, will use a proper FBW throttle from a 'vette or similar.

 

We have adaptors in stock now to use Bosch DBW throttle bodies just in case you didn't know.

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